ok, i know that some people have had this problem, but i thought i would bring it up to see if i can get rid of it. i checked the archives and i found stuff on turbo backfire and other stuff, but i dont think i found the exact problem..

ok, i have a CAI and the rear section of exhaust done and i also have my timing advanced. as of this weekend i will have the hotshot header,catco cat, and courtesy midpipe installed. the car backfires quite a bit, and, it might sound ok every once in a while, but im hoping its not somthing detrimental.

i have herd before that a cause for backfiring could come from having air leaks in the exhaust. my muffler has a small hole under the tip, and i think the break right before the suspension where the rear section connects is leaking too. can that be the problem, or can it be that the car is running rich? or that im not getting enough spark? i just replaced my spark plugs and i had to get new wires about a month and a half ago. but, im pretty positive that it was backfiring before that. is this something that cleaning the MAF wires would fix?

uhh, do you have a cat right now? if you are running a straight pipe, or a hollow one, you will backfire a lot. especially between shifts.

yea, i have the stock cat on right now. im going to replace it this weekend with a CATCO piece

the catco cat, unless your current one is clogged, wont make you any power, the stocker is 3" IIRC.

wow, i hope not. since the header and the B-pipe are 2.5 inchs (or there about) i got a 2.5 inch inlet/outlet cat. just thought i would do it while i was down there. the cat is stock and who knows, it might be clogged.

could the fact that it may be clogged be a reason for the backfire?

no, a clogged cat will just kill your powerband. it would probably be less likely to backfire with a clogged one. check to see if your cat is clogged, if it isnt, then i would return your catco one and invest that money into some pulleys, or some other performance mod.

to late! i aleady have modified it getting it ready for the swap.

ya, the stock nissan cat is boss. it is 2.5" inch almost straight through. really quality piece.

are you 100% sure, without a doubt that it is 2.5 inches straight through? Please tell me yes :-)

as straight as a cat can be, the honeycomb makes it kind of hard to be perfectly straight, but this cat would be perfect for all but heavy boost or nitrous use, and of course, C16 race gas. stay with the stocker, like i said before, and spend that money on pullies, or some other performance part.

well, if the stock one is 2.5" then im going to use the new one. like i said, i spent the money. it was a 14" cat, and i used a tubing cutter to cut .75" off of each end so i cant take it back now.

Okay then whats up with the backfires then. I get 1 if I take my time between shifting. I have the HS gen 4 header (6mos old) stock cat, 2" Greddy Sp catback (1 year old). No leaks that I can find, plugs look fine. I know MaddMatt's car does this and a few others. Some people like it, I hate it. I'm not running super rich like some race cars do, so WTF? Why is this happening?

TIA

Check your injectors they could be leaking as far as the o rings are concerned, or you could be running a tad rich. Also check for exhaust leaks near the exhaust ports.

I used to have a small leak at the head exhaust port but, I fixed it. The injectors I would not have thought of. Okay now for the dumb question, if I am running a tad rich what can I do to fix it. I know JWT could alter my fuel curve but that big dollars. I could clean my TB, air filter again. I don't think changing my fuel pressure regulator would be a good idea. Hummm. I could run a hotter plug. Sorry for the rookie question.

Thanks for your suggestions Mike. I check them out this weekend.

Have a good one,

would cleanbing the wires on the MAF make a difference on the car running rich or not? mine have never been cleaned, and the car is a 93